Conventionally, a card reader which exchanges data with a contact type IC card has been utilized widely. In this type of a card reader, a flexible cable is connected with a plurality of IC contacts which are structured to contact with connecting terminals of an IC card (see, for example, Patent Literature 1). In the flexible cable described in Patent Literature 1, in order to reduce a cross talk between signals transmitted through the flexible cable, a power supply pattern, a ground pattern, a clock signal pattern and a data signal pattern are formed on one face of the flexible cable, and a shield pattern connected with the power supply pattern and the ground pattern is formed on the other face of the flexible cable.
Further, conventionally, in an industry where a card reader is utilized, illegal acquisition of data, that is, a criminal illegally acquires recorded data in a card has been a serious problem. Therefore, conventionally, a flexible cable which is capable of preventing illegal acquisition of data has been proposed (see, for example, Patent Literature 2). The flexible cable described in Patent Literature 2 is connected with signal terminals of the magnetic head. In the flexible cable, both of upper and lower faces of a signal wiring line layer in which a data signal pattern is formed through which a data signal from the magnetic head is transmitted are covered by a protective layer. The protective layer is formed with a disconnection detecting pattern having a disconnection detection function and a short circuit detecting pattern. Therefore, in the flexible cable described in Patent Literature 2, attachment of a signal line for data illegal acquisition to the data signal pattern can be prevented and, as a result, illegal acquisition of data from the flexible cable can be prevented.